Unsurprisingly, Genomic Health (NASDAQ:GHDX) has a low opinion of the analysis of a breast cancer study that competitor Myriad Genetics (NASDAQ:MYGN) referred to in an earlier press release today that appeared to demonstrate the superiority of Myriad's EndoPredict compared to Genomic's Oncotype DX for predicting the risk of breast cancer recurrence.

In a statement to SA, Genomic says, "By only comparing the prognostic ability of six genomic assays, the clinical applicability of this statistical analysis is limited, as it does not address the critical question of whether or not a patient will benefit from chemotherapy. Oncotype DX is the only independent predictor of both prognosis and chemotherapy benefit in both lymph node-negative and node-positive patients and should not be compared directly to prognostic assays that include clinicopathological factors."

Genomic adds, "By combining all node-positive patients, including patients with 4 to 9 positive nodes to create a higher risk profile, Sestak's [the presenter at the symposium] comparison of genomic tests in the node-positive population is not appropriate given that Oncotype DX is not offered to patients with 4 or more positive nodes. Furthermore, this statistical analysis critically failed to produce transparent clinically meaningful results for specific patient groups using relevant lymph node status. We know from our clinical experience in more than 700K patients over the past 10 years that physicians want to use a test that can identify patients who will respond to chemotherapy. This continues to be the key differentiator between Oncotype DX and other genomic tests including all of those evaluated in Sestak's analysis."

Results from a comparative study showed Myriad Genetics' (MYGN+2.8%) EndoPredict (EPclin) was superior to Genomic Health's (GHDX+0.3%) in predicting the long-term recurrence of breast cancer. The data are being presented today at the San Antonio Breast Cancer Symposium.

The study, led by scientists at the Institute of Cancer Research in London, involved 818 women with ER+/HER2- breast cancer (591 node-negative and 227 node-positive) from a study called TransATAC. It compared the power of six predictive signatures: clinical treatment score, immunohistochemical markers, Oncotype Dx recurrence score (RS), breast cancer index (BCI), Prosigna from NanoString Technologies (NSTG+0.9%) and Genomic Health's Oncotype DX.

Each of three second-generation tests (BCI, Prosigna and EndoPredict) outperformed Oncotype DX in predicting the recurrence of breast cancer in node-positive and node-negative patients across zero to 10 years and five to 10 years after surgery.

The predictive power of EndoPredict was almost twice as high as Oncotype DX in node-negative patients and five times higher in node-positive patients across zero to 10 years (defined by likelihood ratio). In the five-to-10-year timeframe, its predictive power was seven times and 13 times greater, respectively, in the two groups of patients. EndoPredict was also superior in classifying node-positive patients as low-risk.

Genomic Health (NASDAQ:GHDX) and Epic Sciences announce an exclusive agreement to commercialize Epic's novel AR-V7 liquid biopsy test in the U.S. through Genomic Health's commercial channel. The blood-based test detects the V7 variant of the androgen receptor protein (AR-V7) in the nucleus of circulating tumor cells (CTC) – information that can help guide treatment selection in patients with metastatic castration-resistant prostate cancer (mCRPC).

AR-V7 expression has been associated with resistance to hormone therapy drugs called androgen receptor signaling (ARS) inhibitors. A recently published study in JAMA Oncology demonstrated that mCRPC patients with AR-V7-positive CTCs had significantly better clinical outcomes when treated with taxane chemotherapy as compared to hormonal treatment with ARS drugs. The data underscore the potential for an AR-V7 predictive test to allow advanced prostate cancer patients to avoid ineffective therapies and to receive chemotherapy at an earlier stage when it may be more beneficial.

Under the terms of the agreement, Genomic Health will have exclusive distribution rights to market and sell the AR-V7 liquid biopsy test in the U.S. beginning in early 2017. It will be offered through Genomic Health's commercial channel to enable physicians to order the test and view the results through the current physician portal. Genomic Health will also make an equity investment in Epic. Specific financial terms are not disclosed.